The present invention relates generally to Floppy Disk Drive Control Units, and more particularly to a control information unit which performs a plurality of kinds of controls by means of outputting control information appropriate to each kind of control of the floppy disk drive.
In a floppy disk drive (called FDD for short), the following functions which the FDD is to be equipped are occasionally changed depending upon the needs of customers, such as the presence of a READY signal which indicates a predetermined part thereof is in a ready state for the operation of the floppy disk drive, the data output level, the presence of a calibration signal which is an initial movement of a head to a predetermined track on a disk, the lighting state of the front light emitting diode (called LED for short).
As shown in FIG. 1, the principal part of the conventional control information output unit is a large scale integrated circuit (called LSI for short) so that the LSI is equipped with various control functions. LSI 9 has selecting terminals 10 which are to be connected to jumper lines (or strap pins) 11. And predetermined kinds of controls are selected by means of switching the connection between each of the selecting terminals 10 and each of the jumper line 11. However, since there are numerous kinds of controls to be selected, if the number of selecting terminals are increased, a printed circuit board (called PCB for short) on which the LSI is mounted has to become larger. Additionally, the number of the selecting terminals cannot be increased beyond a certain limit. Accordingly, all the controls are divided so as to be distributed to several LSIs. However, the conventional control information output unit has the following disadvantages:
1. It is troublesome to connect each jumper line (or strap pin) to each selecting terminal;
2. If the number of selecting terminals are increased, the PCB has to become larger, and then, in turn, the FDD has also to become larger;
3. If the required functions are distributed to the several LSIs, the number of different kinds of LSIs and PCBs are increased so that the number of manufacturing processes are increased accordingly and thus the cost of the FDD becomes higher.